Y Combinator Demo Day, where 47 startups are taking the stage to pitch investors and press, continues to roll along. Here are short descriptions of the second group of presenting companies (the descriptions in the headlines come from the companies themselves). As we mentioned earlier, it's a smaller batch of startups this time around , and since many of them are presenting on an off-the-record basis, this is the last group that we'll be able to write about today.

Y Combinator Demo Day, where 47 startups are taking the stage to pitch investors and press, continues to roll along. Here are short descriptions of the second group of presenting companies (the descriptions in the headlines come from the companies themselves).

Screenhero is a screen-sharing tool that goes beyond simply showing what’s happening on one screen to let people collaborate together in real-time. With Screenhero, two people can be actively working on the same screen together, distinguished from each other with a uniquely colored mouse pointer. Since the app launched in December, Screenhero says it has seen 76 percent monthly growth — and in March alone its user numbers have tripled, with staffers from Facebook, GitHub, and Salesforce using the tool at work every day. Screenhero’s first goal is to take on WebEx, which it dubs a “dinosaur” in the presentation and collaboration space.

The company relates what it has built to YC alum Dropbox, since it’s “one of those products that lots of people want, but you have to get a lot of little things right” in order for it to actually be useful. Read more about Screenhero here.

Paying with slabs of plastic is an antiquated practice. PayTango wants to let you make purchases with your fingerprint. Its technology converts biometric data into traditional card data so it can integrate with existing point of service hardware. That means with just an additional fingerprint reader any store can quickly get set up with PayTango. In the immediate future, the startup plans to work with gyms, restaurants, and convenience stores. But its founder says “We can replace membership cards, loyalty cards, and even ID cards. This is just the beginning.”

While payment cards may be on the way out, PayTango will have to compete with a slew of mobile wallets that are based on your phone. PayTango may need to rely on its strength in security, and focus on businesses where verified identity is critical. That might not be your local quickie mart. Read more about PayTango here.

Mobile optimized Strikingly is the website builder for the mobile age. Since its launch seven months ago, over 25,000 websites have been built using its tool and the startup is seeing 40 percent revenue growth. Strikingly’s platform allows users with little or no development background to create a global optimized website in around 30 minutes.

The founders are aiming to do for website building what Twitter has done for blogging, simplify it, and bring up the example of a blind person who easily created their website on Strikingly. “Mobile has reopened the entire website building market,” the founder asserted, viewing their market as the 75 percent of US small businesses like event planners that still don’t have a unique website.

Prizeo is a startup that runs raffles to let fans of brands and celebrities donate to causes and win prizes for their social media influence into actual funding for charitable causes. The company already counts boy band One Direction, Olympic swimmer Michael Phelps, and singer Alicia Keys as users of its platform; and at Demo Day, the company announced a partnership with talent agency superpower William Morris Endeavor, which has selected Prizeo to be the preferred digial partner for all its clients.

According to Prizeo, it’s not only charities that benefit from celebrity- and brand-oriented philanthropy: Raffles are a great way to collect rich consumer data, making Prizeo a unique way to monetize and expand influence. The potential here is big, the company says — there are tens of thousands of “influencers” with hundreds of millions of fans around the world, and brands have told the company that they are willing to spend some $50,000 per campaign. Read more coverage of Prizeo here.

Designed to replace fashion magazines, StyleUp delivers daily, personalized fashion advice emails to women. The emails show off an outfit tuned to the recipient’s taste and that day’s weather, and they’re getting a stunning 70 percent open rate. That’s much better than the 14 percent industry average. The fashion magazine market is worth $2 billion but it’s dying out. Some top mags saw a 15 percent to 20 percent drop in newsstand sales last year. Meanwhile Style Up is seeing 20 percent monthly growth. Brands will likely be willing to pay to get in front of StyleUp’s users. While it might not be revolutionary, translating an important offline market to the web and augmenting it with personalization can be an easy route to success.

Ebay of designer goods Lollipuff attempts to take the risk out of buying designer goods online by serving its customers with an authentication layer on luxury items from Chanel, Louboutin, and Herve Leger.

Since its soft launch in January, the platform has fulfilled over $45,000 in orders, growing 10x in 3 months. The startup has also seen 13 percent month-over-month user growth in the same amount of time.

Founder Fei Deyle came up with the idea after starting a successful blog as a designer authenticator. Deyle brings up the crux of the buying designer goods online problem in one statistic: 75% of Herve Legier sold on eBay is fake “Would you spend $3k on ‘Chanel’?” Eventually she’d like to scale this authentication process by a combination of software and human expertise.

Billing itself as “Kickstarter, but only for pre-orders,” Swish says it is filling a gap that is deliberately left open by Kickstarter, which emphatically states on its official website that it is a crowdfunding platform and “not a store.” Swish says that today, individual hardware creators are creating their own sales and pre-order software, since there is no good solution out there — until now. Swish has made a full-service pre-order platform that handles listings, payments, escrow, and fulfillments. It seems to be hitting a nerve: Since launching last month, Swish has already become profitable. Going forward, Swish says it aims to be the marketplace on which a new generation of hardware sales will take place.

How do ecommerce shops know which products to sell and how much to sell them for? Semantics3 wants to use big data to answer those questions. Its audacious goal is to index all the products and all the prices on the web in one centralized location. It then sells a data license or API access to ecommerce merchants. This lets them see who else is selling the products they’re selling, how much they’re charging, how their prices are changing, and what products are doing well. And beyond traditional ecommerce, Semantic3 wants to help app developers and other verticals as well.

If it can sell a $12,000 a year license to just the top 1% of the 2 million US ecommerce merchants, it could start earning $240 million a year and help a new wave of commerce entrepreneurs succeed. Read more coverage of Semantics3 here.

Medisas is a a software as a service startup that wants to replace the piece of paper (!) that doctors use to transfer information to each other between shifts.

Medias founder Nitin Shanharam brings up a scary statistic that 66 percent of all serious medical errors stem from errors on these notes, resulting in the deaths of 10k people every month.

Optimized for web tablet and mobile, Shanharam assert that their SAAS powers a better doctor shift handoff and is a $1 billion market, “Enterprise sales happen fast when people are dying,” he says. He sees the opportunity as much bigger than just the handoff notes, which he calls “the spine of the medical record market.” “We can eventually save the lives of hundreds of thousands of people,” he says.

Swapbox is a system of automated kiosks for people to pick up their packages at their convenience by entering in pin codes sent to their mobile devices. The aim here is to make it so that people “never miss a delivery” again, a pain that the Swapbox folks say they know too well: In a clever part of their Demo Day pitch, Swapbox’s co-founder said his team was not wearing company logo t-shirts due to a missed UPS delivery.

Swapbox, which currently has 18 kiosk locations active in San Francisco and has inked a deal for a 15 kiosk pilot in Houston, claims that they have a leg up on Amazon Lockers (and, presumably, YC alum-turned-Google acquisition Bufferbox) because it’s an independent company — “Simply put, Amazon Lockers only work for Amazon,” Swapbox says. “Everybody can use a Swapbox.” Charging $2 per package, Swapbox says that it can quickly scale up to a $150 million annual revenue run rate with 10,000 locations — and that’s just 10 percent of the addressable market. Read our earlier coverage of Swapbox here.

“We are not simply giving startups dumb money,” says Wefunder’s co-founder. His company is an equity crowdfunding platform that creates rich profiles for startups and lets anyone invest in exchange for owning part of the dream. Or at least it will when the JOBS Act is up and running.

Investors can cash out when their startup goes public, gets acquired, or sells stock on the secondary market. Wefunder will have to compete with FundersClub from the last Y Combinator class and other equity crowdfunders. But if the JOBS Act goes into effect as expected, it could make bottom tier venture capitalists obsolete. That’s because like top tier VCs, Wefunder believes the crowd can add value along with their cash. With 60 investors instead of a round of six comes an army of evangelists, recruiters, marketers, and testers who could give their startups an edge. Read more coverage of Wefunder here.

Zenefits wants to eliminate the pain involved in offering employee benefits and health insurance for smaller companies. After going through this difficult process as a two-time founder, Zenefits founder Parker Conrad knew there was an easier way.

“Usually setting up health benefits involve a couple of weeks and a dozen trips to the fax machine,” Conrad says, “Zenefits is ‘set it and forget it,’” mechanizing a process that has thus far been completed using people and paper.

With Zenefits all a small business needs to do is enter a new employee’s 401k info like name, email, salary, stock options, and hire date, and the startup generates an offer letter and a flow for getting insurance memberships up and running.

The service is offered free to clients, but makes revenue as a form of lead generation for insurance companies, making a $50k a year commission per company. “It’s rare to have a free service to clients with such significant reoccurring revenue,” Conrad says. Read more coverage of Zenefits here.

Teachers spend an unbelievable amount of time grading tests. Terascore is building a tool to let these educators create and administer tests online. That means a lot less time checking to see if everyone knows the capital of Idaho. Terascore piggybacks on the trend of everyone carrying smartphones and tablets, so teachers don’t need to book computer lab time to give a test. They’ll also be able to give students real-time feedback to improve learning.

In a surprising move, Terascore’s business model is to get teachers, not school districts, to pay for its platform. The districts are just too slow moving, but the startup believes teachers will pay $9 a month and change their behavior to get more of their precious off-hours back. Read more coverage of Terascore here.

Lawdingo purports to have created the most efficient way to conduct legal services, with an online platform where lawyers and clients can connect, consult, and even exchange payments. According to the company, with its growing consumer traffic levels and more than 600 lawyers plugged into its service, Lawdingo today is comparable in scope and scale to some of the largest law firms in the world. The site lets people search for help using natural language — type in “I hate my wife,” for example, and you get results for divorce lawyers (no kidding).

This is a big market: Legal services is a $250 billion market annually in the US, and law firm advertising is a $4.5 billion market. This startup aims to “elegantly” address both sides. Read more about Lawdingo here.

Meldium is a single sign-in layer for teams, an account and password manager alternative to the horribly inefficient and insecure spreadsheet most companies currently use.

With Meldium, a given team signs up for a single Meldium account, and members can use it in the form of a browser extension, enabling sign ins for some 400 independent apps, including Box, Github, Salesforce, Box and Google Apps.

“When you fire someone you know they’re out,” founder Boris Jabes said, on the benefits of Meldium versus something like Google Docs to hold sensitive login information. The startup currently has 2,000 users and companies seem to be adopting Meldium from the bottom up because of the problem it solves, “My office manager can use this!”

The founders estimate the size of the market as $1.3 billion a year, with 55 million knowledge workers and 2 percent of that paying for the premium version. “It’s 2013 and we have these amazing cloud services managed with a spreadsheet,” Jabes reiterates. Read more about Meldium here.

Goldbely connects its customer base of “Food Explorers” with the most interesting foods from iconic restaurants all over the country, delivering Chicago deep-dish pizza, Texas barbecue, Buffalo chicken wings, and the like to anywhere in the US within a matter of hours. Goldbely prides itself on shipping these items in top-notch condition to ensure that they taste exactly like they would on site.

And it seems to be taking off. Goldbely, which today announced a partnership with Facebook Gifts, says it just broke $100,000 in total sales and is seeing 100 percent month-over-month growth since its late 2012 launch, with 50 percent of its customers coming back as repeat users. Goldbely says it’s targeting a $11 billion market that is incredibly fragmented and dominated by lackluster brands — the top three players in the food gifting space are Omaha Steaks, 1-800 Flowers, and Harry & David, not exactly gourmet food providers. Read our earlier coverage of Goldbely here.